Silica is found almost everywhere in nature, and represents
almost 1/3 the mass of the earth’s crust. Vitreous Silica is the generic term
used to describe all types of silica glass, and manufacturers refer to the
material as either Fused Quartz or Fused Silica.
Fused Silica is an entirely synthetic material, and is
technically the purest glass. It has the highest temperature characteristics of
any glass, and it often begins as pure silicon gas. Because of the way fused
silica is made, it has superior ultraviolet performance to natural quartz and is
ideal for applications such as UV transmitting optics.
We at VENTURE SCIENTIFIC® take utmost care to ensure highest
quality standards, we select quartz raw material after carefully testing the
material for the required standards for selected application.
We supply different sizes and grade of quartz tube such as
thick wall quartz tubes, large diameter quartz tubes U & C shape quartz tubes,
quartz capillary Tube, Two/Four hole thermocouple tube, One end closed
(Flat/Dome) shape Quartz Tubes, Quartz Test Tube and other special shaped quartz
items according to customer’s design.
We are also engaged in design and development of quartz
product for researchers and industries to ensure the quality standards, purity
and temperature range are achieved.
OUR CAPABILITIES
Quartz Glassblowing
Quartz Coldworking
Quartz Machining
Complex Custom Fabrications
Fused Quartz Products
Clear Fused Quartz Tubing
Clear Fused Quartz Rod
Discs & Plates
Microscope Slides
Quartz Flasks
Quartz Beakers
Quartz Crucibles
Quartz Dishes
Quartz Test Tubes
Quartz Standard Joints
Quartz Boats
Quartz Trays
Quartz Wools
Quartz Frits
Quartz Ampoule
Quartz Beads
Custom Fused Quartz
Tolerance of quartz tubes:
OD tolerance 0.1 to 3mm (as per tube dimension)
Wall thickness tolerance 0.1 to 1mm (as per tube dimension)
Siding (max) 0.1 to 0.8 (as per tube dimension)
Ellipticity (max) 0.1 to 3mm (as per tube dimension)
Curvature (max) 2% to 5% (as per tube dimension)
Tolerance of quartz rods:
OD tolerance 0.1 to 3mm (as per tube dimension)
Diameter tolerance 0.1 to 1mm (as per rod dimension)
Thermal Properties
Thermal Conductivity
1.37(W/m°K)
Coefficient Of t\Thermal Expansion(0~1000°C)
2560
Normal Operating Temperature
Continuous Usage
~1050°C
Non Continuous Usage
~1200°C
Strain Point
~1070°C
Annealing Point
~1140°C
Physical Properties
Thermal Conductivity
Units of Measure
Value
Density
gm/cc (lb/ft3)
2.18
Porosity
(%)
0.01
Tensible Strength
106 Pa
48.2
Young’s Modulus
106 Pa
71.5
Hardness
Kg/mm2
580
Thermal Conductivity
W/m°K
1.37
CHEMICAL PROPERTIES OF FUSED QUARTZ / SILICA
Fused quartz (transparent) and fused silica (translucent) are amorphous products
resulting from high temperature treatment of naturally occurring quartz crystals or sand
(SiO2). Fused quartz has a nominal purity of 99.99%, and fused silica 99.90%. Fused
quartz and silica are attacked by phosphoric acid at temperatures in the range of 150
degrees C or higher, and by hydrofluoric acid at all temperatures.
PHYSICAL & THERMAL PROPERTIES OF FUSED QUARTZ / SILICA
Fused quartz and silica have an extremely low coefficient of thermal expansion which
imparts a high resistance to thermal shock. Our fused quartz products can be heated to
1050 degrees C, or higher (1100 degrees C), and immersed in cold water without resultant
physical damage. Annealing point is 1140 degrees C, strain point is 1070 degrees C,
fusion point is between 1700 and 1800 degrees C.
Devitrification of fused quartz does not usually occur at temperatures below 1100 degrees
C under normal conditions. High temperatures accelerate devitrification particularly in
the presence of surface contaminants such as alkaline solutions, salts and vapors. To
prevent deposit of salts, fused quartz should be handled with gloves. Radioactive
materials, hydrogen and certain metals also accelerate devitrification.
Devitrification can be identified, as fused quartz cools below 250 degrees C, by a hazy
film caused by micro-fine cracks. Devitrification can be forestalled by washing the
quartz surface in a 10% solution of hydrofluoric acid for several minutes at room
temperature, followed by a series of rinses in distilled or deionized water, followed by
rapid drying.
ELECTRICAL PROPERTIES OF FUSED QUARTZ / SILICA
Fused quartz and silica have excellent electrical strength that remains highly stable
with temperature variation. Quartz resistivity (10 to 17th power) ohms/cc at 25 degrees
C is in the order of (10 to 17th power) ohms/cc at 1000 degrees C.
Purity and Tolerance / ppm
Quartz, though being abundant in Earth’s crust, takes purification before putting into
applications.
Purity is a critical indicator for quartz material. The semiconductor industry, in
particular, demands
high purity quartz because impurities, even in trace amounts, may impact
heat-resistance, wear-resistance and other electrical properties of semiconductor
components.
To meet requirements of the semiconductor industry, impurities in processed quartz must
be
kept to ppm level.
Al
Fe
Ca
Mg
Ti
Mn
B
K
Na
Li
Cu
Co
Ni
Oh
16
0.4
0.6
0.4
0.1
0.1
0.8
2.0
2.3
0.5
5.7
<0.02< /td>
0.03
≦3
Coefficient of Thermal Expansion
10-6/°C
0.54
Specific Heat
J/Kg.°K
735
Dieletric Strength
Ac-kv/mm (volts/mil)
28
Dieletric Constant
@1MHz
3.80
Index of refraction @ 587.6nm
1.44
Note:- The above information is believed to be correct but does not purport to
be all inclusive and shall be used only as a guide. The information in this document
is based on the present state of our knowledge and is applicable to the product with
regard to appropriate safety precautions. It does not represent any guarantee of the
properties of the product. Venture Scientific® shall not be held liable for any
damage resulting from handling or from contact with the above product.